As used herein, a dynamic 3D object is defined as a three-dimensional virtual object that dynamically changes its shape through deformations or relative motions of its parts. The definition of dynamic can be extended to not only include geometrical changes but also changes in appearance, color, texture, and other attributes of the object. Examples of a dynamic 3D object are a virtual person walking or a virtual heart beating. A static 3D key-model is herein defined as a model of a dynamic 3D object in a fixed pose with a particular set of attributes. Typical representations are static wireframe or triangulated surface models, which can be stored, e.g., in form of VRML files.
Various computer graphics applications require the rendering of virtual three-dimensional (3D) objects, including dynamic 3D objects. Such virtual 3D objects are often created and modeled offline and then visualized later in a real-time scenario. In addition to geometry, color, and texture information, object motion and deformation are principal attributes of dynamic 3D objects. Examples of animated objects in the present sense include, for example, an animated figure, a deformable object, or a 3D object that changes its shape over time, or some combination of the foregoing and/or other attributes. One of these areas where a framework for displaying and rendering virtual objects is already intrinsic to its technology is Augmented Reality (AR) visualization. This is a technology that augments views of the real world with computer-generated objects. Optical or video images of the real world are combined with computer graphics in real time; real and virtual objects appear to coexist in the same scene.
Applications of AR can be found in manufacturing, health-care, entertainment, infotainment, military, and other fields. See for example, Ronald Azuma, Yohan Baillot, Reinhold Behringer, Steven Feiner, Simon Julier, Blair MacIntyre, “Recent Advances in Augmented Reality,” IEEE Computer Graphics and Applications, vol. 21, no. 6, pp. 34-47, 2001. For an example of a video-see-through AR system for computer assisted medical procedures, see F. Sauer, F. Wenzel, S. Vogt, Y. Tao, Y. Genc, and A. Bani-Hashemi, “Augmented Workspace: Designing an AR Testbed,” IEEE and ACM Int. Symp. On Augmented Reality—ISAR 2000 (Munich, Germany, Oct. 5-6, 2000), pages 47-53; and Frank Sauer, U. Joseph Schoepf, Ali Khamene, Sebastian Vogt, Marco Das, and Stuart G. Silverman, “Augmented Reality System for CT-guided Interventions: System Description and Initial Phantom Trials,” in Proceedings of SPIE's Conference of Medical Imaging 2003: Visualization, Image-Guided Procedures, and Display, vol. 5029, February 2003, pp. 384-394.